Radiator Mister

[garhawk]

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Hey folks,

Just thought you might like to know how my new mister works on the DD Series 60 in my Eagle 20.

During this past summer, the big engine rose to 217 degrees while climbing a 2,000 ft hill here in Middle Tennessee.  The ambient temperature was @ 100 deg.  Although no alarms sounded, nor did the DDEC threaten to shut down the engine, that high temperature number is my self imposed limit so, we pulled to the side and allowed the engine to cool.  With our summer travel plans including some western states with much higher hills and temperatures plus, reading other Board Members experiences with overheating, I decided to install a mister.

Here's how I did it with what was available to me and the layout of the coach. 

1)  Plumbed 1/2" pvc from house water system to a 1/2" copper pipe with 100mm holes drilled approximately 2" apart and mounted across the top of the radiator.

2)  Installed a 12vdc solenoid in the water line at the entrance to the radiator compartment with two switches - one on the driver's instrument panel and the second at the radiator.  The second switch is for testing the mister without a helper located at the driver's panel.

It was a fairly simple, straightforward installation taking the better part of a day.  The first try was disappointing as the solenoid would not shut off.  After some consultation with the manufacturer, it was determined that since I had mounted the solenoid at the highest point in the plumbing, air was being trapped and the unit could not build sufficient pressure to shut itself off.  Once the air was worked out, the solenoid worked perfectly and water flooded the radiator. 

Sitting still, the mister dumps what appears to be a large amount of water.  I may have drilled the holes a might on the big size.  When the water squirts out it is more than a mist.  However, my mind envisions what could be a mist when at speed and a 50 mph wind is blowing across it.

Here's the only test result I can report to you because the weather
has been on the cool side.  With the outside temperature at between 70 and 75 degrees, on the highway driving 55 mph and, the engine temperature reading 187 degrees, two 3 second squirts (with about a 3 second interval) brought the engine temperature to 185 degrees.  Subsequent squirts had no further effect on the engine temperature.

Scienfic minds will no doubt boggle at all this highly technical engineering and testing but I'm more interested in what ya'll think.  Does 2 degrees of engine temperature drop, from 187 degrees at 70 to 75 degrees of ambient air temperature, equate to 10 degrees of engine temperature drop from 215 degrees when the air temperature is at 100 degrees?

[bevans6]

""1)  Plumbed 1/2" pvc from house water system to a 1/2" copper pipe with 100mm holes drilled approximately 2" apart and mounted across the top of the radiator.

Sitting still, the mister dumps what appears to be a large amount of water.  I may have drilled the holes a might on the big size.  When the water squirts out it is more than a mist.  However, my mind envisions what could be a mist when at speed and a 50 mph wind is blowing across it. ""

Well, given that a 100mm hole is a tad under 4", and drilled at 2" centers in a half inch pipe, you may have chosen too large a hole size at that!   

You meant to say 1.00 mm, no doubt...

Brian

[luvrbus]

Gary, your 60 Series should have shut down at 217 at 210 a warning buzzer better have that checked they disable the shut down on fire trucks and other emergency vehicles could be what someone has done that to your engine 

A 60 series will run fine at 200 degrees water temp, not so good with hi temps on air intake at the inter cooler that is the only thing I have saw misters used for a 60 series,if your 60 series is running hot up the turbo boost that is a great thing about a 60 series more boost will cool one down were extra boost will not help the older 2 strokes me I am not a fan of band aids like the misting systems they are ok for patios in AZ lol

good luck

[garhawk]

Brian,

You are absolutely correct, I left out the decimal.  Thanks for the correction.

Clifford,

I really appreciate the heads up on the Series 60 running temperature.

Normal gauge reading when in cruise is 190.  It is only on a considerable uphill pull that the temperature begins to climb and, the arbitrary limit of 215 that I had set was from others who had advised me.  I value your opinion and will act accordingly.

How would you go about checking for the absolute correct temperature?  I have a Silverleaf system tied to the ECU, is that sufficiently accurate?  The Silverleaf and the original Eagle panel gauge agree.  That is, as close as you can read the original panel gauge.

While you are correct in that a mister is somewhat of a 'bandaid', if it will keep my engine within the safe temperature zone using little effort
and money, at my age and financial status I just might have to live with it. 

[Lin]

I think that you will have to wait for a hot day to get an idea of how well the system works.  If you have 185 degree thermostats, they will not let the engine temp drop anymore.  Therefore, you can only guess at this point.

[luvrbus]

Gary, if your 20 still has the piece of crap hydraulic fan drive do away that and convert over to the belt fan drive one from a Prevost works like a charm without a lot of fab work and the whole setup will cost you less than a fluid loss from a broke hose JMW

[belfert]

My bus has a Series 60 from the factory.  It runs right at about 195 degrees once warmed.  It will get as high as 200 degrees on a steep grade, but it usually sits right at 195.

The radiator was shot when I got the bus and the bus shut down due to high temp once on my trip home when I drove the bus home from the dealer.  I watched the temp gauge closer after that.  I took the radiator to a radiator shop and they found that stop leak had been used to close up pinhole leaks.  They offered me a new core or they could close up the bad tubes.  I choose to get a new core and the bus has never overheated since.  (I also replaced the water pump at the same time since it was easy to replace with the radiator out.)

[usbusin]

Gary, you want your "misters" to put out a "mist".  You do not want to flood the radiator core with a stream.  The cooling will work if the water (the mist) will evaporate.  The evaporation is what accomplishes the cooling effect.  Hope this helps.

GaryD

[dougyes]

We used Patio Misters from Chinamart. They produce a fine mist. We fastened it to the intake grille with wire ties. The mister emitters can get clogged so a fine inline filter is advised. It did the trick on our series 60 going up the grapevine on a hot summer day.

[Oonrahnjay]

  Gary, you want your "misters" to put out a "mist".  You do not want to flood the radiator core with a stream.  The cooling will work if the water (the mist) will evaporate.  The evaporation is what accomplishes the cooling effect.  Hope this helps.
GaryD 

     Yeah, Gordon Jennings once printed an article (take that for what it's worth) that said that for the equivalent (I'm assuming mass) air and water for the cooling of a subject item, water is about 80 times more efficient at removing heat than air.  Water going through a phase change (i.e.. evaporation) removes about 400 times as much heat.  So Gary D is exactly right here - the effect you're looking for is evaporation.  Water that just splashes through the radiator isn't going to do you much good. 

     If you wanna keep up the Thomas Edison work there, you could run your bus until your way over thermostat opening with no water, then try it again with the system you have now (1.00 mm is about 40 thou -- I dunno why them Cannaydjins can't use feet and inches and speak English like Jesus did in the Bible -- so that a pretty big hole).  You could go back and do your test a third time with misters with a tiny spray hole to maximize evaporation.   I'm gonna guess that once you're a good bit above thermostat opening, any water will make a good difference but a fine spray will be notably better.  To be a really effective comparison, you'd need enough misters to move as much water as you're moving with the 40 thou holes, but I'm gonna guess that you'll get all the cooling you need with less than that.

[Kirby-XL40-FL]

Ditto on mist vs. water. 

[lvmci]

Hi All, commuting in my MCI 5A with a 8V71 between LV&LA & vacationing in Az & Ca, I usually run into hill climbs in the heat. I bought a simple misting system from home depot, flex tubing, hard tubes wth brass mister ends assorted hose & connectors from irrigation isle, a 12v pump & RF on/off switch from Frys, the hose I was going to connect to the drain of fresh water tank, when I had thoughts about distilled water gallons or 2 1/2 gallon jugs that might keep sprayer nozzels from plugging up, definitly in need of auxillary cooling on hills, but how long would I use the sprayers? Before to after each hill? Just when it starts to heat up, or maybe just filter the water inline and use it liberally. tom...

[lorna]

We had to build a misting system for the Blue Bird while sitting in the parking lot of a Lowe's (ambient temps were over 100°F). We  were moving (NC to NM) and had a spare 30 gal Valterra tank, 12vDC water pump (too much gpm's), an on/off toggle switch, extra wiring (we salvaged all the wiring from the Eagle before we scrapped it) and a couple of drip irrigation garden kits packed in the bus (our moving van). A few extra parts (misters) were required but it made a pretty good system. The ladies in the garden dept were nice enough to let us fill the water tank with their hose (then gave us directions to take a primary road into NM instead of heading down the interstate in even higher temps than we had been experiencing). We were blowing the misters from the garden kit apart due to water pressure. Much ;later, we bought a small 1 gph Shurflo pump that will power the misters without blowing them to pieces. I do think a filter would be a good addition to any misting system. Nice thing about using the garden/drip irrigation parts is we can replace/repair at any Lowes, Home Depot, ACE hardware or True Value Hardware. I want to use filtered/softened water from our on board domestic water tank for the misting system (inline backflow valve will be used). The mineral build up was surprising for something that was only used for three days. I have two years to get it all done (in addition to finishing the bus conversion while living in a campground).

David simply watched the temp and when it started climbing, he flipped the pump switch on until the temp dropped at which point he turned the pump off.  It was a bandaid. We still have an engine that is running very hot for some reason. We do need to pull and possibly replace some of the radiator hoses. We suspect they are so old and weak, they may be collapsing. Or there may still be a couple of rocks stuck in a hose (bus was used to transport whitewater rafters in SC/NC/TN). But we don't know since we haven't moved the bus much except for the 1700 mile trip out here and the 150 mile trip in December to get to our current location (snow all over... no overheating). The radiator was flushed out (full of sand, rocks & a couple pounds of solder from a bad repair job someone did) re-soldered, new radiator cap and new fluids as we passed thru Texas (East Radiator Repair in Longview Tx... good place, nice people).

[rv_safetyman]

There have been lots of thread on misters.  We had a pretty good one going on our Eagles International forum:

http://www.eaglesinternational.net/forum/viewtopic.php?f=5&t=2446

In that thread, I made the following post:

I stayed away from this thread for a while to see what would develop.

I do not have a problem with the radiator/water temperature, but many of you have followed my trials and tribulations with my charge air cooler. It is located on the side opposite the radiator (could not make it work on the radiator side and did not want to put am extra heat load on the radiator). I have worked very hard to get the air flow across the charge air cooler maxed out and have hit the limit. Under all but long climbs, the air inlet temperature is acceptable. However, on long pulls, the air temperature really starts to climb and the only way I can control it is with a mister system.

I have tried all kinds of nozzles including those intended for chicken coop cooling (neat nozzles).

From all of the various threads on the subject, I got ideas for different approaches. One theory is to point the nozzles away from the radiator to cool the air before it hits the fins. Never got that to work. Next, I tried fine spray heads (all kinds and numbers) and never really got much temperature reduction.

My last approach has been to use two of the nozzles that I furnish with my fire suppression system. They flow a bit over 1/2 gallon per minute with a large spray pattern. I am basically drenching the radiator. I use an electric switch and operate it for about 3-4 seconds on and 6-15 seconds off - depending on what my air temperature is. My SilverLeaf reads the air inlet temperature transducer and I can see an very fast response and major temperature reduction.

There are always huge debates on the forums about what kind of water to use. I use water straight out of the house supply tank (no filter, but it would be a good idea) and have not noted a calcium buildup. If I do, I will deal with that problem with vinegar or some variation of Lime Away type chemical.

As noted in my post, I have tried a lot of different systems and found a lot of neat nozzles.  One of the neatest nozzles were intended for use in large chicken raising facilities. 

One of the problems I found in the misting approach was the rather small distance between the inlet screen on the side of the bus and the radiator/air to air.  That really makes it difficult to get a good spray pattern on the radiator.

As noted, I have not found the misting approach to do much good.  My "flooding" approach works well for me and the delivery of the water is not nearly as critical.

Jim

[skihor]

I made a 2 head mister system for each rad in our MC 5A. Each head flowed @ 2GPH. It sprayed slightly more than evaporated.  @ approx. 8" from the rads each head has a 8" "pattern"
I tried a 4 head 3/4 GPH each that wasn't as effective.
I ran out of our fresh water tank with a Shureflo 2.8 with an inline fuel filter on 1/4" lines. I used "all thread" rods for mounting the "heads. The biggest drawback was the "deposits" left behind. After awhile CLR wouldn't touch it, or anything else, for that matter. I had to remove them and have them "boiled". 
I've since added 2 additional rads and my heating issues are almost gone.

Don & Sheila